5 files changed, 34 insertions, 12 deletions
diff --git a/clang/lib/CodeGen/CGClass.cpp b/clang/lib/CodeGen/CGClass.cpp
index af8cbbc48c2..4848d7565d4 100644
--- a/clang/lib/CodeGen/CGClass.cpp
+++ b/clang/lib/CodeGen/CGClass.cpp
@@ -2180,7 +2180,7 @@ void CodeGenFunction::EmitLambdaToBlockPointerBody(FunctionArgList &Args) {
     return;
   }
 
-  EmitFunctionBody(Args);
+  EmitFunctionBody(Args, cast<FunctionDecl>(CurGD.getDecl())->getBody());
 }
 
 void CodeGenFunction::EmitLambdaDelegatingInvokeBody(const CXXMethodDecl *MD) {
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 221d132ee0b..4a427d540f6 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -1824,8 +1824,8 @@ LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
     return LV;
   }
 
-  if (const FunctionDecl *fn = dyn_cast<FunctionDecl>(ND))
-    return EmitFunctionDeclLValue(*this, E, fn);
+  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
+    return EmitFunctionDeclLValue(*this, E, FD);
 
   llvm_unreachable("Unhandled DeclRefExpr");
 }
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 3ec890383c9..ce1b44559dc 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -643,13 +643,12 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
     DI->EmitLocation(Builder, StartLoc);
 }
 
-void CodeGenFunction::EmitFunctionBody(FunctionArgList &Args) {
-  const FunctionDecl *FD = cast<FunctionDecl>(CurGD.getDecl());
-  assert(FD->getBody());
-  if (const CompoundStmt *S = dyn_cast<CompoundStmt>(FD->getBody()))
+void CodeGenFunction::EmitFunctionBody(FunctionArgList &Args,
+                                       const Stmt *Body) {
+  if (const CompoundStmt *S = dyn_cast<CompoundStmt>(Body))
     EmitCompoundStmtWithoutScope(*S);
   else
-    EmitStmt(FD->getBody());
+    EmitStmt(Body);
 }
 
 /// Tries to mark the given function nounwind based on the
@@ -672,6 +671,17 @@ static void TryMarkNoThrow(llvm::Function *F) {
   F->setDoesNotThrow();
 }
 
+static void EmitSizedDeallocationFunction(CodeGenFunction &CGF,
+                                          const FunctionDecl *UnsizedDealloc) {
+  // This is a weak discardable definition of the sized deallocation function.
+  CGF.CurFn->setLinkage(llvm::Function::LinkOnceAnyLinkage);
+
+  // Call the unsized deallocation function and forward the first argument
+  // unchanged.
+  llvm::Constant *Unsized = CGF.CGM.GetAddrOfFunction(UnsizedDealloc);
+  CGF.Builder.CreateCall(Unsized, &*CGF.CurFn->arg_begin());
+}
+
 void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
                                    const CGFunctionInfo &FnInfo) {
   const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
@@ -726,9 +736,15 @@ void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
     // Implicit copy-assignment gets the same special treatment as implicit
     // copy-constructors.
     emitImplicitAssignmentOperatorBody(Args);
-  }
-  else
-    EmitFunctionBody(Args);
+  } else if (Stmt *Body = FD->getBody()) {
+    EmitFunctionBody(Args, Body);
+  } else if (FunctionDecl *UnsizedDealloc =
+                 FD->getCorrespondingUnsizedGlobalDeallocationFunction()) {
+    // Global sized deallocation functions get an implicit weak definition if
+    // they don't have an explicit definition.
+    EmitSizedDeallocationFunction(*this, UnsizedDealloc);
+  } else
+    llvm_unreachable("no definition for emitted function");
 
   // C++11 [stmt.return]p2:
   //   Flowing off the end of a function [...] results in undefined behavior in
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index b07e903b49f..98c090fa149 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -1136,7 +1136,7 @@ public:
   void EmitConstructorBody(FunctionArgList &Args);
   void EmitDestructorBody(FunctionArgList &Args);
   void emitImplicitAssignmentOperatorBody(FunctionArgList &Args);
-  void EmitFunctionBody(FunctionArgList &Args);
+  void EmitFunctionBody(FunctionArgList &Args, const Stmt *Body);
 
   void EmitForwardingCallToLambda(const CXXMethodDecl *LambdaCallOperator,
                                   CallArgList &CallArgs);
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index d0f34dddca3..c34f8332699 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1406,6 +1406,12 @@ CodeGenModule::GetOrCreateLLVMFunction(StringRef MangledName,
     DeferredDeclsToEmit.push_back(DDI->second);
     DeferredDecls.erase(DDI);
 
+  // Otherwise, if this is a sized deallocation function, emit a weak definition
+  // for it at the end of the translation unit.
+  } else if (D && cast<FunctionDecl>(D)
+                      ->getCorrespondingUnsizedGlobalDeallocationFunction()) {
+    DeferredDeclsToEmit.push_back(GD);
+
   // Otherwise, there are cases we have to worry about where we're
   // using a declaration for which we must emit a definition but where
   // we might not find a top-level definition: